Fog inhibitor for photographic emulsions



Pmne'a mr. 14, 1939 2,150,102. roe mnmrroa roa' rno'rocnarmc mots IONS

Samuel E. Sheppard and 'Waldemar Vanselow,

Rochester, N. Y.;=.asslguors, by mesne assignmcnts, to Eastman Kodak Company, Jersey City, N. 1., a corporation of New Jersey No Drawing. Application Hayd, 1936,

Sclfldl N0. 78,464

s Galms. (oi; 95-1) This invention relates to fog inhibitors for photographic emulsions and to photographic emulsions containing them.

It is known that photographic emulsions par.- ticularly ultra-sensitive emulsions, or those containing color sensitizers exhibit a tendency to form a deposit of silver in the emulsion. This deposit extends more or less uniformly over the entire emulsion and'is known as fog. Photographic fog is of two local and general. Local;fog is formed by exposure of the film or plate at undesired points, as by a light leak in the camera. General log or, asit is sometimes known, chemical fog, is formed in a number of ways. It may be caused by the conditions. under which the film or plate is stored, such as conditionsof high temperature or unusually long time of storage. The nature of the emulsion,

as where emulsions are highly sensitive may also The primary object of the present invention is to provide anti-fogging or fog inhibiting agents for ultra-sensitive photographic emulsions and to thereby increase the stability of the emulsions.

A further object is to provide anti-fogging agents which do not markedly lower the sensitivity of the emulsion.

These objects are accomplished by incorporat ing in the emulsion an alicyclic amine containing at least two NH; groups either or both of which may be unsubstituted or substituted. with an alkyl radical or with certain other radicals;

The compounds which we use as fog inhibitfing agents are-alicyclic amines having two or negative. emulsion, particularly a silver halide more NH: groups in'the same nucleus or in dif- -ferent nuclei. These NH:- groups may be in-- either a benzeneor in a naphthalene type of ring and they may be unsubstituted or substituted with a single alkyl radical, or aceto radical, or'

emulsion. The emulsion used may be one which is intended to be used directly after emulsiflca-- tion or one whichis subjected to ripening by chloride),

treatment at a high temperature or by treat ment with ammonia.

The compounds used according to our invention may be divided into two classes. The first class includes those compounds in which the amino groups are contained in a single ring of the benzene or the naphthalene type. The secnd class includes those in which the amino groups are in difierent rings each of the benzene or naphthalene type\ joined as in diphenyl. Under the first class of compounds we have used the phenylene diamines and their derivatives. These include para-phenylene diamine, metaphen'ylene diamine and ortho-phenylene diamine; amino substituted derivatives, such as para-amino dimethyl aniline (sulfate), para- .amino vdiethylaniline, para-amino dibutyl aniline (hydrochloride), para-amino methyl acetanaline .and tetramethyl phenylene diamine; ring substituted derivatives, such as 2:5-diamino toluene (hydrochloride), 2:5-diamino anisole (hydro- 2z4-diamino toluene, 2:4-diamino phenyl (hydrochloride) and 2:4-diamino anisole (hydrochloride). The second class of compounds includes benzidine and its derivatives and diphenyl' methane derivatives. These include. benz'ldine, amino substituted derivatives of benzidine, such as tetra-methyl benzidine and diacetyl benzidine; ring substituted derivatives of benz'idine, such as ortho-tolidine and dianisidine. The diphenyl methane derivatives include p:pdiamino diphenyl methane; amino substituted derivatives such as tetra-methyl diamino diphenyl methane; p:p'-tetra-ethyl diamino diphenyl *methane; ring substituted derivatives, such as 2:2'-4:4'-tetra-amino 5:5-dimethyl diphenyl methane (sulfate).

In the diphenyl methane type of compound, which has the following structural formula:

'the CH2 group between the rings may be replaced by other'groups, such as -(CH2) 11-, -+S-, O.

In these coinpoundsthe benzene nucleus may Y be substituted by'a naphthalene nucleus which emulsion will vary from .01 gram to 5 grams per 1000 cos. of wet emulsion. The following table will serve to illustrate amounts which we have found to be satisfactory. In each case the amount specified is used with 1000 ccs. of a gelatino-silver halide emulsion.

.Grams p-Phenylenediamine .01-1 p-Aminodimethylanilihe .05-1 p-Aminodiethylaniiine .05-1

' p-Aminodibutylaniline .05-5 p-Aminomethylacetanilide 1-5 Tetramethylphenylenediamine .1- .2 2:5-diaminotoluene-2HCI .01-1 2:5-diaminoanisole-2HC1 .05-1 m-Phenylenediamine .2-5 2:4-diaminotoluene 1-5 2:4-diaminophenol-2HC1 .05-1 2:4-diaminoanisole-2HC1 .05 o-Phenylenediamine 1-5 Benzidlne 1 Tetra-methylbenzidine 1 Diacetyl benzidine 1ess than" 1 o-Toli:iin.e-. do 1 Dianisidine 1 p-p-Diaminodiphenylmethane 1 Tetra-methyldiaminodiphenylmethane 1-5 p p Tetra ethyldiaminodiphenylmethane 1 -5 2:2'- 4:4- tetra amino 5:5'- dimethyldiphenylmethane (sulfate) -less than 1-$ It is to be understood that more or less of the anti-fogging agent than the amount stated above may be used. Generally; however, if a greater amount is used in the emulsion, either no in creased fog inhibiting effect is obtained, or there is a decrease in the sensitivity of the emulsion.

Emmple I A gelatlno-silver halide negative emulsion which contained sensitizing agent and which had been .made in the usual way and had a pH of 7.4,

was heated on a water bath sufllciently to melt it.

To a 1000 cc. portion of this'emulsion there were added 50 ccs. 01' an ethyl alcohol solution containing the .5 gram of para-phenylene diamine. The resulting solution was thoroughlymixed and wascoated on glass plateadried, and incubatedv for '1 days at 60? C. toobtain a fog test." The fogging produced at the end or this time was.

very much less than that produced on a plate coated with the emulsionto which no iog inhibiting agent had been added.

.lmple 1r A. g'elatino-s'iger halide negative emulsi which contained'iensitiling mat and which had.

been made in the usual way and had a pH of 7.4,

was heated on a water bath sumcie'ntly to melt it.

Toa1000cc,portionoi'thiaemulsiontherewas added 100 cos. of a water solution of p-aminodibutyl aniline hydrochloride containing 1 gram oi this compound. the resulting solution'was thoroughly mixed and was coated on glass plates,

' the emulsion to which no this time was very much less than that produced on a plate coated with the emulsion to which no fog inhibiting agent had been added.

Example III A gelatino-silver .halide negative emulsion which contained sensitizing agent and which had been made in the usual Wayland had a pH of 1.4, was heated on a water bath sufliciently to melt it. To a 1000 cc. portion of this emulsion there were added 100 ccs. oi! an ethyl alcohol solution containing 1 gram of .benzidine. The resulting solution was thoroughly mixed and was coated on glass plates, dried and incubated for '7 days at 60 C. to obtain a fog test. Theiogging produced at the end of this time was very much less than that produced on a plate coated with fog inhibiting a ent had been added.

The fog inhibiting agents which we have described may be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-color sensitized emulsions they may also be used in orthochromatic, panchromatic and X-ray emulsions. They may be used with or without color sensitizing dyes and if used with the sensitizing dyes they may be added to the emulsion before or after the dyes are added. Various silver salts may be used as the sensitive salt, such as silver bromide, silver iodide, silver chloride or mixtures of these. The dispersing agent may be gelatin or other colloids, such as collodion, albumin, or suitable cellulose organic derivatives or artificial resins.

It is to be understood that we contemplate as limlude'd within our invention all modifications and equivalents coming within thescope of the appended claims.

What we claim and desire to secure by Letters Patent of the United States is:

1. Aphotographic emulsion comprising gelatin having sensitive silver salts dispersed therein and. containing as an anti-foggant 0.2to 1 gram per 1000 cos. of wet emulsion of a phenylene dlamine.

2. A photographic emulsion comprising gelatin I havingsensitive silver salts dispersed therein and containing as an anti-foggant 0.2 to 1 gram per 1000 ccs. of wetemulsionioi paraphenylene diamine.

3. A photographic emulsion comprising gelatin having sensitive silver salts dispersed therein and containing as an anti-foggant .05 to 1 gram per an amino dialkyl aniline hydrochloride.

a; A s l -t ne silver halide emulsion ton l... ing as an anti-iosaant 0.2 to 1-gn. m per 1000 ccs.- 01 wet emulsion of a phenylene dl'amlne.

m n. wanpman vansnnow. 

